ThinKing July 2019: A small bush with a big impact

08.07.2019

 

Saves time and effort and delamination is no issue.

Fibre-reinforced plastics in particular are tough materials to deal with when it comes to joining and connecting. There is always the risk and fear of delamination when screws are driven in. This is where the MEBUX Light Weight threaded bush from IMS Verbindungstechnik GmbH & Co. KG can help. The bush is self-tapping, which does away with the threading process entirely and reduces assembly time as a result. The bush expands when a screw is driven in to prevent the screw being unscrewed again. It can also be used later as a connecting element in a component.

The Development Agency for Lightweighting Baden-Württemberg presents this innovation in the July 2019 edition of the ThinKing. Leichtbau BW GmbH uses this label to showcase excellent lightweight technology products or services from Baden-Württemberg every month.

At a glance:
- Self-tapping bush: Faster assembly and less work
- High reverse torque keeps the bush in place without jamming
- Unscrew-proof in the component
- No delamination of CFRC
- Can be fitted into the component later as a connecting element
- Can be driven right into the component for spacer-free assembly

The MEBUX Light Weight bush has been developed by IMS Verbindungstechnik GmbH & Co. KG based in Neuenstein specially for use with composites. “You only have to drill one hole for assembly and can then screw the bush directly into the workpiece. The bush is self-tapping, which saves time and effort because you no longer have to cut a thread, for example”, explains Pascal Fischer, IMS product manager. The bush can also be machined reliably without the need for special tools. What is more, the special form also ensures that the MEBUX LW expands in the workpiece when a screw is driven in, explains Fischer. “This results in very high reverse torque, which prevents the bush becoming detached from the component when the screw is unscrewed again,” explains production manager Sascha Haberhauer. Expansion also means that no adhesives are needed and the bush can also withstand permanent stresses, such as frequent screwing in and out, continues Haberhauer. The collar also ensures that the bush is firmly fixed in place.

No need to worry about delamination
The MEBUX LW can be driven into the component flush with its surface to enable spacer-free installation. “The bush can also be fitted subsequently into a complete CFRC or GFRC component as a fixing element. This means it does not have to be inserted into the workpiece during lamination,” says Fischer. Lamination is a good cue: Delamination is considered a real problem with composite materials in particular. “This refers to the way in which a component made of composite materials is damaged if the composite material fractures into separate layers or fibres debond when a screw is driven in. The special geometry of our bush prevents delamination during assembly and stops the component getting damaged,” explains Haberhauer.